This invention generally relates to slotted drains and more particularly to slotted drains having upper and lower grates which are initially variable in both height and slope and which may then be rigidly fixed with respect to each other at a predetermined height and slope with respect to an attached drain pipe.
Slotted drains have been widely used in the past for draining surface water from roadways, parking lots and airport runways, for example. The open slot at the top of the drain is placed level with or immediately below the surface to be drained so that surface water will flow directly through the slot and into the drain pipe installed below the ground. Typical open top slotted drains have comprised structures such as those shown in U.S. Pat. No. 3,815,213 to Evans et al. which was issued on Jun. 11, 1974.
The drains disclosed by Evans et al. generally include lower pipe sections which have been longitudinally split along an upper side to form a narrow, longitudinal slot in which a grate is secured to extend along the length of the pipe. The grate is formed by a pair of spaced bearing plates rigidly secured on either side of the narrow slot. Various arrangements of spacer members extend between the two grate members and are welded to the inside surfaces of each bearing plate. The disclosed spacer members comprise either solid cross bars which extend perpendicularly to the axis of the pipe or a sinusoidal plate member disposed between the two bearing plates. Other types of spacer members which have been used in the past include flat, vertically extending plates disposed between and welded to the inside surfaces of the bearing plates.
Methods have also been developed by which to properly set the elevation and slope of the drain within a trench. Two examples of such methods are disclosed in U.S. Pat. No. 4,844,655 to Aleshire and U.S. Pat. No. 4,878,782 to Beattie et al. Both Aleshire and Beattie et al. utilize posts or spikes to support the drain at the proper elevation within the trench while concrete is poured into the trench surrounding the drain. Typical methods of raising the height of a drain such that it may be placed within deeper trenches have included stacking sections of the drain itself in the case of channel drains, or stacking separate grates on top of one another in the case of slotted drain pipes. Examples of stacked drainage channel systems are found in U.S. Pat. No. 4,640,643 to Williams, U.S. Pat. Nos. 5,026,202 and 5,106,231 to Thomann.
Past drainage system designs have also included means for sloping the drain while keeping the upper edges thereof level with the surface of the drainage area. These designs have included trench drains having built-in drainage slopes such as those disclosed in U.S. Pat. No. 4,640,643 to Williams and U.S. Pat. No. 5,066,165 to Wofford et al.
One known method of providing a slotted drain pipe with a grate which is sloped with respect to the drain pipe involves sloping the grate with respect to the axis of the drain pipe such that one end of the grate extends considerably below the inside surface of the drain pipe. This method, however, either necessitates an additional manufacturing step thus adding to the cost of the drain or will increase the chances of debris clogging the pipe. That is, the grate must be cut along the angle of the slope so as not to extend considerably into the drain pipe or, if left to extend into the pipe, it serves as a potential obstruction which may cause clogging.
Past drainage systems have thus failed to provide for easy adjustment of both the height and slope of the drain. Accordingly, there remains a need for a slotted drain having grates which are adjustably attachable to one another so as to enable both vertical and angular adjustment of one with respect to the other and which may be rigidly secured to one another at a particular slope and height to meet the needs of a particular drainage site.